Effect of Additives on Maximizing Petrol Production from Crude Oil and Investigation of Properties

Md. Ashaduzzaman1,*, Md. Yunus Miah2

1Department of Applied Chemistry and Chemical Engineering, University of Dhaka,

Dhaka 1000, Bangladesh, Tel: +880-2-9661900-73/7402, Fax: +880-2-8615583

2Institute of Fuel Research and Development, BCSIR, Dhaka 1000, Bangladesh

*E-mail address: azaman01@du.ac.bd

ABSTRACT

The objectives of this work were concentrated to investigate the enhancement of petrol distillate

production from crude oil after treating with two additives. Attempts were also made to find out the

mechanisms, those are responsible for enhancing the quantity and quality of petrol from crude oil by

straight run refining process. From this study, it has been illustrated that the yield of petrol was

directly proportional to the lubricating oil and inversely proportional to the bitumen asphalt content in

the hydrocarbon mixture influenced by both physical and chemical reasons. The yield of petrol was

increased ca. 4 % (w/w) when 0.25 % (w/w) additive-1 was used for blending before distillation. The

physical properties of distillate petrol product were studied as well as the chemical quality was

determined by TGA, 1H- NMR and GC-MS photometer.

Keywords: petrol; crude oil; additive; quality; mechanism

1. INTRODUCTION

Distillation of crude oil for petroleum products is a crucial issue regarding to

enhancement of distillate product. The demand of petrol has been increasing day by day due

to increase the number of vehicles production for the modern civilization. Among the various

techniques, catalytic cracking in presence of activating additives1-3

is an important technology

to increase the distillate production. To meet the demand of unleaded gasoline the

construction of new catalytic cracking or distillation and alkylation units have been

established for increasing the yields of high-octane gasoline ingredients and on the exclusion

of low-octane naphthas from gasoline blends4. Quality of the main product has also been

found improved especially octane number of petrol.

Besides, quality of petrol is another concerning factor to the environmentalists because of

global warming due to emission of huge green house gases as combustion products as well as

metal particles in atmosphere. Determination of petrol quality considering physical properties

and chemical compositions by several instruments has been done by many research groups5-7

.

Among these techniques, thermal analysis has been used in the last 30 years for studying the

petroleum and petroleum products. For crude oil, the techniques were normally applied for

studying the oils pyrolysis and combustion8,9

. Thermo-gravimetry (TG) has been used to

International Letters of Chemistry, Physics and Astronomy Online: 2013-04-02ISSN: 2299-3843, Vol. 11, pp 6-16doi:10.18052/www.scipress.com/ILCPA.11.6CC BY 4.0. Published by SciPress Ltd, Switzerland, 2013

This paper is an open access paper published under the terms and conditions of the Creative Commons Attribution license (CC BY)(https://creativecommons.org/licenses/by/4.0)

study the effect of the oil composition on the pyrolysis kinetic of the crude10-13

. There are

many profile production technology available for maximizing distillate production and

quality14

from crude oil which are very complicated and highly expensive to implement in

practice specially in developing and under developing country. Therefore, in many

circumstances by considering the “state -of- the- art” concept production technology can be

changed slightly.

In this study, we implement a blending unit for mixing the crude oil and additives before

charging in a distillation unit. The improvement of petrol quality has been proved by

instrumental means. The mechanisms, which are responsible for recovery of high quantity and

improved quality of petrol, are still unknown although we have elaborately discussed some

clues that would be involved with the high recovery of improved quality of petrol by using

different types of additives in the straight run refining process of crude petroleum.

2. EXPEROMENTAL

2. 1. Materials and methods

The used crude oil was supplied by Eastern Refinery, Bangladesh. Lubricating oils

(additive 1 was purchased from I. B. S. Associates, Aziz Chamber, 6 Jublee Road, Chittagong

and additive 2 was purchased from GMS composite knitting industries ltd., Joydevpur,

Gazipur) were used as activating additives.

Distillation: Distillation was carried out in a distillation system according ASTM D-

1160, Model: PETRODIST 300, Manufacturer: HARMANN PAULSEN. D-2000

HUMBURG 65, GERMANY. Well-stirred crude oil into a flask was weighed by a balance

and then required quantity of additive was mixed. Then the whole apparatus was set up for

carrying out the operation in atmospheric pressure up to 180 °C to collect gasoline distillate.

Thermo gravimetric Analysis (TGA): Model: TGA-50, Manufacturer: SHIMADZU

CORPORATION TESTING & WEIGHING EQUIPMENT DIVISION, KYOTO, JAPAN 1H NMR analysis:

1H NMR Spectra were recorded at 250 MHZ on a Bruker AC250

instrument where CDCl3 and TMS were used as solvent and internal standard respectively.

GC-MS (Gas Chromatography and Mass Spectrometry): Model: GCMS-QP5050A,

Manufacturer: SHIMADZU CORPORATION, JAPAN. The GCMS-QP5050A is a compact,

high performance quadruple mass spectrometer.

3. RESULTS AND DISCUSSION

The used crude oil and additives were thoroughly investigated separately before running

the experiment. The properties of crude oil are furnished in Table 1. One can easily speculate

that the properties of crude oil are not unique. The content of carbon residue and sulfur were

6.6 % w/w and 1.04 % w/w respectively. The additives were analyzed by TGA and 1H-NMR

spectroscopy precisely to define their chemical compositions. Table 2 presents the results of 1H NMR of two additives. The experimental data shows that additive 1 contains lower amount

of aromatic protons than additive 2 whereas, for paraffinic protons an opposite phenomenon is

observed. Results of TGA analysis from fresh crude oil and additives 1 and 2 have been

demonstrated in Table 3. About 33.5 % w/w of crude oil was obtained as gasoline fraction

International Letters of Chemistry, Physics and Astronomy Vol. 11 7

which was collected from the boiling point fraction 35 and 180 °C. The additives contain a

variety of heavy petroleum fractions with lubricating oil, paraffin wax and bitumen asphalt.

Table 1. Properties of crude oil

Properties Values

Density at 20 °C, gm/cc 0.8281

Specific gravity at 15 °C 0.85813

Water content,(V/V)% 0.2

Pour point, °C -27

Flash point, °C 18

Fire point, °C 22

Viscosity, cS at 40 °C 6.12

at 100 °C 1.04

Carbon residue, mass % 6.60

Sulfur content, mass % 1.04

Calorific value, Kcal/Kg 10405.08

Table 2. Type, name and

1H NMR analysis of additives 1 and 2.

Type Name % of aromatic

proton

% of paraffinic

proton

Additive 1 Lubricating oil 1.474 98.526

Additive 2 Lubricating oil 1.801 98.199

Figure 1 shows the variation of the yield of petrol from crude oil in presence of

additives 1 and 2. The production of gasoline (petrol) increased dramatically from 28.88 to

32.84 % (by wt.) when 0.25 % (by wt. of crude oil) of additive 1 was charged. As further

increased the addition of additives, the yield of petrol remained steady at about 31.5 % w/w

up to 1 % w/w. More than 0.5 % w/w additive influenced to lower the production of petrol.

The critical concentration of additive for petrol production was revealed 0.5 % w/w.

8 ILCPA Volume 11

Table 3. Results of thermo-gravimetric analysis of fresh crude oil and different types of additives.

Name Temp.

°C

Carbon

No.

Fresh Crude

oil A1 A2

L.P. Gas Up to 35 C1-C4 0.795 --- ---

Light naphtha 60-110 C6-C7 13.063 --- ---

Gasoline 35-180 C5-C12 33.432 --- ---

Diesel 180-350 C13-C18 47.881 17.640 21.845

-- IBP-270 C5-C18 61.421 1.723 2.429

Lubricating oil 270-400 C15-C18 28.899 51.893 58.575

Paraffin wax › 400 C18-C30 9.484 45.606 37.617

Bitumen asphalt Residue C30-above 0.196 0.778 1.253

IBP= Initial Boiling Point, A1=Additive 1, A2=Additive 2

Table 4 shows the fractional (% w/w) distillation of crude oil containing 0.25 % w/w of

additives 1 and 2. It was observed that 50 % w/w of crude oil was escaped approximately at

261 and 245 °C in presence of additive 1 and 2 respectively. Effect of additives on changing

the boiling point of crude oil reflects the change of physio-chemical properties upon which

Fig. 1. Influence of the variation of additives on the yield of petrol obtained by

atmospheric-vacuum distillation of crude oil in presence of additives 1 and 2.

0.0 0.5 1.0 1.5 2.020

22

24

26

28

30

32

34

Yie

ld o

f p

etr

ol (w

t.%

)

Additives (wt. %)

Additive 1

Additive 2

International Letters of Chemistry, Physics and Astronomy Vol. 11 9

the quality and quantity of petrol production depend. The percentages of light and heavy

fractions present in crude oil would be easily distinguished from this data.

Table 4. Fractional distillation of crude oil with 0.25 % (by wt. of crude oil) additives 1 & 2.

Fraction,

% by wt.

Crude oil with A1

Temperature, °C

Crude oil with A2

Temperature, °C

0 26.09 38.20

10 125.88 114.04

20 166.38 151.38

50 261.15 244.49

70 327.82 308.89

90 427.04 407.62

99 729.94 616.52

Table 5 represents the data of 1H NMR analysis. The results demonstrated that, as the

additives were added incrementally with crude oil, the amount of aromatic protons gradually

increased and the amount of paraffinic protons decreased. Besides, the amount of 1°, 2° & 3°

paraffinic protons and protons of methyl groups (-CH3) attached with the benzene ring

structures were also increased with the increase of additive 1. It is revealed that 6.121 %

protons of methyl groups (-CH3) attached with the benzene ring structures present in petrol

obtained from crude oil containing 1 % (by wt. of crude oil) additive 1. The increase of

paraffinic (-CH3) & aromatic (-CH=) protons boost up the O. N. of petrol produced from

crude oil treated with additive 1 and can be estimated from the following empirical equation.

Table 5. Results from

1H NMR spectra of petrol obtained from fresh crude oil and crude oil

with additive 1 in different percentages.

Name Petrol obtained

from fresh crude oil

Petrol obtained from

crude oil with 0.25 %

A1

Petrol obtained from

crude oil with 1 % A1

Aromatic

protons 3.457 3.910 6.950

Paraffinic

protons 96.543 96.090 93.050

(% by wt. of crude oil)

O. N (Octane Number) = 71 + 0.48 (HA %) + 1.02 (HB %) + 2 (HF %) / 3 (HE %)

where, HA – aromatics protons, HB – olefinic protons, HF – paraffinic 1° protons and HE –

paraffinic 2° protons.

10 ILCPA Volume 11

Table 6 shows the results of TGA of petrol. The variation of the fraction (% by wt.) of

produced petrol with respect to the gradual addition of additive 1 is very important to discuss.

It is evident that when 0.25 % additive was added then L. P gas, light petroleum gas and light

naphthas were increased with respect to the product obtained from without and with 1 % (by

wt. of crude oil) of additive. It is well established that the lighter fractions of petroleum have

average higher octane number.

Table 6. Results of thermo-gravimetric analysis of petrol obtained from fresh crude oil and

crude oil containing 0.25 % and 1 % (by wt. of crude oil) additive 1.

Name Temperatur

e range, °C

Carbon

No.

Petrol from

fresh crude

oil.

Petrol from crude

oil with 0.25 %

A1

Petrol from

crude oil with 1

% A1

L.P. gas up to 35 C1-C4 4.668 8.916 4.830

L. P. gas* 35-60 C5 - C6 12.216 20.629 13.472

Light

naphtha 60-110 C6 - C7 46.519 67.046 52.214

Gasoline 35-180 C5 -

C12 94.667 88.756 94.717

Kerosene >180 C12-

C15 0.665 2.328 0.453

*Liquefied petroleum gas

In the Total Ion Chromatogram (Fig. 2) of petrol obtained from fresh crude oil, it is

revealed that 31 peaks were analyzable. Retention time for the first peak was 1.953 min, mass

spectrum of this (first) peak was 95 % similar with 2-methylbutane and 31 number pear was

tridecane, its emperical formula is C13H28. It is predicted that petrol obtained from fresh crude

oil contained hydrocarbons having carbon number C5 - C13.

The mass spectrums of peak no.14 and peak no. 29 were compared with their similar

mass spectrums of known compounds respectively. From this phenomenon, it is clear that the

peak no. 14 is 2,4-dimethyl hexane shows the base peak 43 and mass peak 114, which are 97

% similar with the mass spectrum of 2,4-di-methyl hexane and the peak no. 29 is n - undecane

shows the base peak 57 and mass peak 156 which are 96 % similar with the mass spectrum of

n-undecane. Total Ion Chromatogram of petrol obtained from crude oil containing 0.25 % (by

wt. of crude oil) of additive 1 is presented in Fig. 3.

There are 38 detectable peaks were revealed in the Figure 3. It is revealed that the first

and the last peaks are 2-methyl butane and n-dodecane respectively. It is also remarkable that

the petrol contains hydrocarbons having carbon number C5 - C12.

The mass spectrum of peak number 12 and peak number 23 are compared with their

similar compounds respectively. Spectrums of cycloheptratriene are 93 % similar with the

spectrum of 1,3,5 – cycloheptatriene where base peak is 91 and parent peak is 92.

International Letters of Chemistry, Physics and Astronomy Vol. 11 11

Fig

. 2.

Tota

l Io

n C

hro

mat

ogra

m o

f pet

rol

obta

ined

fro

m f

resh

cru

de

oil

12 ILCPA Volume 11

Fig

. 3

. T

ota

l Io

n C

hro

mat

og

ram

of

pet

rol

ob

tain

ed f

rom

cru

de

oil

co

nta

inin

g 0

.25 %

(b

y w

t. o

f cr

ude

oil

) ad

dit

ive

1.

International Letters of Chemistry, Physics and Astronomy Vol. 11 13

Table 7. Summarized results of GCMS for petrol.

Product name % of

n-Paraffins

% of

iso-Paraffins

% of

aromatics

% of cyclo-

compounds

Petrol from fresh crude oil 36.7 43.15 11.77 8.37

Petrol from crude oil

containing 0.25% additive 1. 30.23 45.97 12.98 10.34

Table 8. Fractionation of iso-paraffins.

Product name Light iso-paraffins (up to

2, 4-dimethylhexane), %

Heavy iso-paraffins (after

2,4-dimethyl hexane), %

Petrol from fresh crude oil 28.72 14.43

Petrol from crude oil

containing 0.25% of A1 18.9 27.07

Finally, it is revealed from Table 7 and 8 GC-MS results that the percentage of iso-

paraffins, aromatics and cyclocompounds were increased whereas, the percentage of n-

paraffins in petrol was decreased when crude oil was blended with 0.25 % (by wt. of crude

oil) of additive 1. Furthermore, the percentage of light iso-paraffins decreases and heavy iso-

paraffins increases in petrol obtained from crude oil containing 0.25 % (by wt. of crude oil) of

additive 1 is shown in Table 8.

In crude oil additive acts as gum inhibitors for the light petroleum distillate. The most of

them are phenolic, amino and sulfur compounds. Substances containing metals are

recommended occasionally for the same purpose but they do not seem to be true oxidation

inhibitors and their action might depend on immunizing metals dispersing the sludge and

other causes. Asphaltic materials form colloidal solutions in light petroleum fractions and are

the probable emulsifying agents in crude oils. This is indicated by the fact that the dilution of

a crude oil emulsion with a light petroleum fraction, light gasoline tends to stabilize the

emulsion.

Two antagonistic forces exist at the emulsion interface. Surface tension encourages the

coalescence of the dispersed particles while the film of the emulsifying agent discourages

coalescence. The stability of the emulsion depends on the relative magnitude of the two

opposing forces. The emulsion can be broken by increasing the surface tension at the

interface. Additives can take part into an intermolecular reaction with the hydrocarbons of

crude oil. One can easily assumed that the contents of lubricating oil, paraffin wax and

bitumen asphalt in the mentioned additive may have the decisive effect on the distillation

process of crude oil for recovery of high quantity and improved quality of gasoline. To find

out the confirm mechanism further study is also needed.

The reason behind the improvement of petrol quality was some light iso-paraffins were

converted into heavy iso-paraffins. It is evident that 1° (-CH3) and 2° (-CH2-) protons were

substantially decreased but 3° protons (-CH=) were increased therefore, that some n-paraffins

14 ILCPA Volume 11

were changed into iso-paraffins by isomerization and addition reactions. The increase of

aromatic compounds in petrol indicates the enhancement of petrol quality in terms of

especially octane number.

Effect of additives on crude oil for diesel production by vacuum distillation will be

discussed in future.

4. CONCLUSIONS

The demand of petroleum products especially, in transport sector has been increasing

day by day due to the rapid industrialization and urbanization. To fulfill this demand, i.e. to

get sufficient quantity of middle distillate and pollution free fuel, development of petroleum

refining is essentially important.

In this work, a method has been developed for improving the straight run refining

process. It is established that the yield of petrol increases from 28.88 % to 32.84 % (w/w)

when optimum quantity 0.25 % (by wt. of crude oil) of additives 1 is used. Maximum

quantity of additives depends upon the type of additives that's why optimum quantities of

additives used in this process of distillation are different for different additives. By TGA, 1H

NMR and GCMS analysis, it is demonstrated that the quality of products (octane number of

gasoline) which mainly depend upon the fractions of iso-paraffins and aromatics

hydrocarbons also improved when optimum quantity of additive 1 is used.

This method mainly gives the opportunity to petroleum refiners to get their desirable

quantity of petrol on the one hand and improve the quality of the products on the other hand.

To explain the total mechanism involves in this process, further study is also needed.

For implementing the technology, no change of existing technique of refinery is necessary; a

small arrangement for mixing the crude oil and additives is needed before the distillation

operation.

References

[1] M. Miah Yunus, Technol. Topl. Acel. USSR 3 (1989) 10-13.

[2] N. A. Koval Chuk, M. Yunus Miah, Nefteperepab. Nefttekhi 10 (1989) 5-7.

[3] M. Miah Yunus, D.Sc. thesis (1992) 235.

[4] Encyclopedia of Britanica, 6th

edition, New York, 1994-2000.

[5] S. Husain, S. N. Alvi and R. R. Nageswara. Analyst 116 (1991) 405-408.

[6] R. Dhole Vivek, G. K. Ghosal, Journal of Liquid Chromatography 18(12) (1995)

2475-88.

[7] M. Miah Yunus, B. M. Aliev, A. I. Gasanov, Neft Gaz. USSR (1-2) (1992) 46-48.

[8] J. H. Bae, Soc Pet Eng AIME (1972) 211-219.

[9] M. V. Kok, M. R. Pamir, J Anal Appl Pyrol 35(2) (1995) 145-56.

[10] A. Ciajolo, R. Barbella, Fuel 63(5) (1984) 657.

[11] M. Ranjbar, G. Pusch, J Anal Appl Pyrol 20 (1991) 185-96

International Letters of Chemistry, Physics and Astronomy Vol. 11 15

[12] O. Karacan, M. V. Kok, Energy Fuel 11 (1997) 385-91.

[13] O. Karacan, M. V. Kok, Journal of Thermal Analysis 52 (1998) 781-8.

[14] J. Black, J. Petrunia, T. R. Powell, Petroleum Technology Qarterly 3(2) (1998) 65-70.

16 ILCPA Volume 11